1. Field of the Invention
The invention relates to the field of lighting and/or signaling, especially for automotive vehicles. More particularly, the invention relates to a method for controlling an overall light beam emitted by an automotive vehicle headlamp and obtained by adding intermediate beams produced by at least two illuminating means, and to light-emitting modules that may allow such controlling methods to be implemented.
2. Description of the Related Art
An automotive vehicle is equipped with headlamps, or headlights, intended to illuminate the road in front of the vehicle, at night or in case of low luminosity. These headlamps may generally be used in two lighting modes: a first “high-beam” mode and a second “low-beam” mode. The “high-beam” mode allows the road far in front of the vehicle to be brightly illuminated. The “low-beam” mode procures more limited illumination of the road, but one that nevertheless ensures a good visibility without however dazzling other road users. These two lighting modes are complementary. The driver of the vehicle must manually change mode depending on the circumstances, at the risk of inadvertently dazzling another road user. In practice, the need to change lighting mode manually may lead to a lack of reliability and sometimes prove to be dangerous. Furthermore, the low-beam mode sometimes procures a visibility that is unsatisfactory for the driver of the vehicle.
To improve the situation, headlamps equipped with an adaptive lighting function (especially known by the acronym AFS for “adaptive frontlighting system”) have been proposed. Such an adaptive lighting function is intended to automatically detect, for example by processing images acquired by an on-board video camera, a road user liable to be dazzled by an illuminating beam emitted in high-beam mode by a headlamp, and to modify the outline of this illuminating beam so as to create a zone of shadow in the location of the detected user. The advantages of such an adaptive lighting function are multiple: greater user comfort, better visibility relative to a headlamp in low-beam mode, higher reliability as regards the mode change, greatly decreased risk of dazzle, and better road safety.
Document EP2280215 describes an example of an automotive vehicle headlamp lighting system equipped with an adaptive lighting function. The system comprises four primary optical elements, in each of which three light sources are associated with three respective light guides, and four secondary projecting optical elements, as it happens lenses, respectively associated with the four primary optical elements. The light emitted by each light source penetrates into the associated light guide and it exits via an exit end of the guide, of rectangular shape. The arrangement of the primary optical elements and of their associated secondary optical element means that the light emitted by each optical-guide exit end is projected by the secondary optical element so as to form, in front of the vehicle, one vertical luminous section. The luminous sections produced partially superpose in the horizontal direction. It is the actuation of the light sources, which may be turned on independently of one another, selectively, that is used to obtain the desired illumination and produce a complementary beam of the high-beam type that does not dazzle other road users. The beam is thus divided into a plurality of luminous sections that it is possible to activate or deactivate. The adaptive illuminating beam that may thus be produced merely by electronically controlling the turn-on of the light sources, and without mechanical movement of an additional shielding part, is especially known as a matrix beam.
Moreover, it is increasingly common to see automotive vehicles equipped with a directional lighting function, more widely known by the acronym DBL (for dynamic bending light), in which the objective is to illuminate the road and its sides when the vehicle turns. The headlamp is mounted so as to be able to pivot about a substantially vertical axis of rotation, and therefore when the vehicle corners, the projected beam output by the headlamp is oriented toward the inside of the corner rather than along the longitudinal axis of the vehicle.